Cleaning devices are often used to clean items, such as motor vehicles, walls, decks, sidewalks, etc. Such devices are usually mobile and are used at the site of a cleaning job. As is understood by those working in the art, cleaning fluids used in such devices typically consist of a mixture of heated water, steam, and/or a chemical solution that is delivered to an area or article to be cleaned. While heated water, steam, and/or a chemical solution are typical fluids, other fluids or combination of fluids, are contemplated for use in embodiments of the present disclosure. In any case, fluid supplied to the cleaning wand assembly often and preferably is heated. That fluid temperature is preferably maintained over a variety of operating conditions.
A number of prior art devices are directed to certain aspects of the present invention. For instance, U.S. Pat. No. 4,142,496 to Saito et al. (“Saito”), which is incorporated herein by reference in its entirety, discloses an exhaust gas recirculation system for internal combustion engines to reduce nitrogen oxide emissions.
Similarly, U.S. Pat. No. 6,901,746 to Nishiyama et al. (“Nishiyama”) discloses an exhaust gas recirculating circuit for mixing an exhaust gas into intake air, and is also incorporated herein by reference in its entirety. Nishiyama provides an exhaust gas recirculating circuit adjusting valve and controller that recirculates a predetermined amount of the exhaust gas for reducing NOx (nitric oxide (NO) and nitrogen dioxide (NO2)) when the absorbed NOx accumulation amount is a predetermined value or less, and recirculates the aforementioned predetermined amount or more of exhaust gas to bring an air fuel ratio into a rich state when the adsorbed NOx accumulation amount exceeds a predetermined value and is to be released.